JP2003093336A - Electronic endoscope apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a spectral image capable of clearly displaying a blood vessel pattern without providing a light source part with a narrow-band pass filter for optical wavelengths. SOLUTION: A spectral imaging signal is generated form Red, Green, and Blue (RGB) color imaging signals by means of matrix arithmetic part 436 provided in an image processing body 43 and displayed on a display monitor 106 via a changeover part 439.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic endoscope device used for medical treatment or the like.

[0002]

2. Description of the Related Art Recently, in an electronic endoscope apparatus using a solid-state image pickup device, attention has been paid to spectral imaging in which a narrow bandpass filter is combined. 2000 10
"Trial on development and clinical application of Narrow Band Imaging (NBI)" by Sano, Yoshida, Kobayashi and others at the Japan Gastroenterological Endoscopy Society Meeting held in March. In comparison with the conventional image with the illumination light by the RGB frame-sequential method, the image with the illumination light by the RGB frame-sequential method with a narrow spectral characteristic is used for the biological mucous membrane (tongue). It has been shown that the fine structure of (part) can be accurately extracted. Also, at the General Assembly of the Japan Gastroenterological Endoscopy Society held in May 2001, the presenter announced the results of clinical application in the gastrointestinal tract, and the conventional endoscopic images for both the stomach and the large intestine area were presented. It was shown that the fine structure which was not extracted was extracted. The endoscope apparatus shown in this conventional example uses a frame-sequential type and its R
The GB color filters are changed to three optical narrow wavelength bandpass filters, and three spectral images are generated by the illumination light that has passed through the respective narrow optical wavelength bandpass filters.

[0003]

However, this conventional example has the following problems. (B) An optical wavelength narrowband bandpass filter having a spectral characteristic to extract a fine structure must be provided separately from a normal endoscope device, and a space for installing this filter is required, The entire endoscope becomes larger. (B) In order to obtain a spectral image with a new bandpass filter, it is necessary to replace or add an optical wavelength narrowband bandpass filter provided in the light source section. An object of the present invention is to solve the above problems and obtain a spectral image without providing an optical wavelength narrow band bandpass filter for a spectral image in the light source section.

[0004]

In order to solve the above-mentioned problems, the invention described in claim 1 is an electronic device for irradiating a subject with light from a light source for illumination and obtaining a color image signal by a solid-state image sensor. The endoscopic device is characterized by including an arithmetic unit that generates a spectral image signal from the color image signal.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Before describing the first embodiment according to the present invention, a matrix which is the basis of the present invention will be described below. Here, the matrix is a predetermined coefficient used when generating a spectral image signal from a color image signal acquired for generating a color image (hereinafter referred to as a normal image). Further, following this description, a correction method for obtaining a more accurate spectral image signal and a method for improving the S / N ratio of the generated spectral image signal will be described. This correction method, S / N
With regard to the improvement method of, it may be used as necessary. FIG. 1 shows a color image signal (here, R, G, and B for simplification of description, but in the complementary color solid-state image sensor, G, Cy, and Mg are used as in the embodiments described later.
(A combination of Ye may be used)), and is a conceptual diagram showing a signal flow when a spectral image signal corresponding to an image corresponding to a more narrow optical wavelength band is generated. First, the color sensitivity characteristics of each of R, G, and B as an electronic endoscope device are converted into numerical data. Here, the R, G, and B color sensitivity characteristics are characteristics of output with respect to wavelengths obtained when a white subject is imaged using a white light source. The color sensitivity characteristics of R, G, and B are as follows.
It is shown to the right of each data as a simplified graph.
Further, the color sensitivity characteristics of R, G, B at this time are respectively defined as n-dimensional column vectors R, G, B. Next, narrowband bandpass filter F1 ・ F2 ・ F3 for spectral image to be extracted
(As foresight information, I know the characteristics of a filter that can efficiently extract the structure. The characteristics of this filter are that the wavelength band is approximately 590 nm-approximately 610 nm, approximately 530 nm-approximately 550 nm, approximately 400 m-approximately 430 nm.
Each nm is a pass band. ) Is converted into numerical data. The term “substantially” is a concept including about ± 10 nm in wavelength. The characteristics of the filter at this time are respectively n-dimensional column vectors F ₁ · F ₂ · F ₃ . Based on the obtained numerical data, the optimum coefficient set that approximates the following relationship is obtained. That is,

[Equation 1] The elements of the matrix such that The solution of the above optimization proposition is mathematically given as R
Assuming that the matrix representing the color sensitivity characteristics of G and B is C, the matrix representing the spectral characteristics of the narrowband bandpass filter to be extracted is F, and the coefficient matrix to be obtained is A,

[Equation 2] Becomes Therefore, the proposition shown in equation (1) is equivalent to finding the matrix A that satisfies the following relation.

[0006]

[Equation 3] Here, since the number n of point sequences as spectral data representing the spectral characteristic is n> 3, the equation (3) is not a one-dimensional simultaneous equation, but is given as a solution of the linear least squares method. That is, equation (3) may be solved as a pseudo simultaneous equation. If the transposed matrix of the matrix C is ^t C, then (3)
ceremony

[Equation 4] Becomes ^{Since t} CC is an n × n square matrix, equation (4) can be regarded as a simultaneous equation with respect to the matrix A, and its solution is

[Equation 5] Is given. Matrix A obtained by equation (5)
With respect to, by performing the transformation on the left side of the equation (3), it is possible to approximate the characteristics of the narrow band pan pass filter F1, F2, F3 to be extracted. The above is the description of the matrix which is the basis of the present invention. Next, a correction method for obtaining a more accurate spectral image signal will be described. In the above description of the processing method, the light flux received by the solid-state imaging device such as CCD is accurately applied when the light flux is completely white light (all wavelength intensities are the same in the visible range). That is, when the RGB outputs are the same, the approximation is optimal. However, under an actual endoscope, the illuminating light flux (light flux of the light source) is not a perfect white light, and the reflection spectrum of the living body is not uniform, so the light flux received by the solid-state image sensor is not a white light (color is I have arrived, so the RGB values are not the same). Therefore, in the actual processing, in order to more accurately solve the proposition shown in the equation (3), it is desirable to consider the spectral characteristics of the illumination light and the reflection characteristics of the living body in addition to the RGB color sensitivity characteristics. Here, the color sensitivity characteristics are set to R
(Λ), G (λ), and B (λ), an example of the spectral characteristic of the illumination light is S (λ), and an example of the reflection characteristic of the living body is H (λ).
The spectral characteristics of this illumination light and the reflection characteristics of the living body are
The characteristics do not necessarily have to be the characteristics of the apparatus or the subject to be inspected, and may be, for example, general characteristics acquired in advance. If these coefficients are used, the correction coefficient k _R · k _G · k
_B is

[Equation 6] Given in. When the sensitivity correction matrix is K, it is given as follows.

[0007]

[Equation 7] Therefore, the coefficient matrix A is as follows by adding the correction of the expression (7) to the expression (5).

[0008]

[Equation 8] Also, when actually performing optimization, if the spectral sensitivity characteristic of the target filter (F1, F2, F3 in Fig. 1) is negative, it becomes 0 on the image display (that is, the spectral sensitivity characteristic of the filter). Of the optimized sensitivity distribution is used, and it is also allowed to allow a part of the optimized sensitivity distribution to be negative. In order to generate a spectral sensitivity characteristic with a narrower band than a broad spectral sensitivity characteristic, by adding a negative sensitivity characteristic to the target F1, F2, and F3 characteristics, as shown in Fig. 1, the sensitivity is increased. It is possible to generate a component that approximates the band that has. Next, a method for improving the S / N and accuracy of the generated spectral image signal will be described. This S / N ratio improving method further solves the following problems by adding it to the above-described processing method. (A) If any of the original signals (R, G, B) in the above processing method becomes saturated, the characteristics of the filters F1 to F3 in the processing method are the characteristics of the filter that can efficiently extract the structure (ideal and Characteristics). (If only two signals among R, G, and B are generated, the two original signals are not saturated). (B) When a color image signal is converted into a spectral image signal, a wideband filter is used to generate a narrowband filter, resulting in deterioration of sensitivity and a reduction in the component of the generated spectral image signal. N ratio is not good.

As shown in FIG. 2, the method of improving the S / N ratio is to irradiate illumination light several times (for example, n times) in one field (one frame) of a normal image (general color image).
Times, n represents may be changed to irradiate in two or more integer) to (irradiation intensity in each round. In Figure 2, I ₀
Through In. This can be realized only by controlling the illumination light. By this, it is possible to reduce the intensity of irradiation once, and it is possible to prevent each of the RGB signals from being saturated. Further, the image signals divided into several times are added in the subsequent n stages. This makes it possible to increase the signal component and improve the S / N ratio. The above is the description of the matrix that is the basis of the present invention, the correction method for obtaining an accurate spectral image signal that can be implemented together with the matrix, and the method for improving the S / N ratio of the generated spectral image signal. is there. Next, a specific configuration of the electronic endoscope apparatus according to the first embodiment of the present invention will be described with reference to FIGS. 2 and 3. FIG. 2 is a conceptual diagram showing the integral calculation of the color image signal, and FIG. 3 is an external view of the electronic endoscope device according to the present embodiment. Note that the other embodiments described below also have the same appearance. The electronic endoscope apparatus 100 includes a scope 10
1, an endoscope apparatus main body 105 and a display monitor 106. In addition, the scope 101 is provided on the guiding middle portion 102 to be inserted into the body of the subject, the distal end portion 103 provided at the distal end of the guiding middle portion 102, and the side opposite to the distal end side of the guiding middle portion 102. The angle operation unit 104 for instructing a bending operation or the like is mainly configured. The image of the subject acquired by the scope 101 is subjected to predetermined signal processing in the endoscope apparatus main body 105, and the display monitor 1
At 06, the processed image is displayed.

Next, referring to FIG. 4, the endoscope apparatus main body 1
05 will be described in detail. Note that FIG. 4 is a block diagram of the electronic endoscope apparatus 100. As shown in the figure, the endoscope device main body 105 mainly includes a light source unit 41, a control unit 42, and a main body processing device 43. In the present embodiment, the description will be given assuming that the endoscope apparatus main body, which is one unit, has the light source section and the main body processing apparatus that performs image processing and the like, but these are separate units and are removable. It may be configured in any manner. The light source unit 41 is connected to the control unit 42 and the scope 101, and emits white light (including the case of not being completely white light) with a predetermined light amount based on a signal from the control unit 42. In addition, the light source unit 41 includes the lamp 1 as a white light source.
5. It has a chopper 16 for adjusting the amount of light and a chopper drive unit 17 for driving the chopper 16. The chopper 16 has a dot 1 as shown in FIG.
7a is provided as a center, and a disk-shaped structure having a predetermined radius r is provided with a cutout portion having a predetermined length in the circumferential direction. The center point 17a is connected to a rotary shaft provided in the chopper drive unit 17. That is, the chopper 16 makes a rotational movement around the center point 17a. Also,
A plurality of cutouts are provided for each predetermined radius. In the figure, the cutout portion has a maximum length = 2πr × 180 degrees / 360 between the radius r and the radius r _1.
Degree, width = rr ₁ . Similarly, from radius r ₁ to radius r ₂
, The maximum length is 2πr ₁ × 90 degrees / 360 degrees, the width is r ₁ -r ₂ , and the maximum length is ₂ between radius r ₂ and radius r _3.
πr ₂ × 30 ° / 360 °, width = r ₂ −r ₃ . (The respective radii are r> r ₁ > r ₂ > r _3. ) Note that the length and width of the cutout portion in the chopper 16 are examples, and the present invention is not limited to this embodiment. Further, the chopper 16 has a protrusion 160a extending in the radial direction substantially at the center of the notch. It should be noted that by switching the frame when the light is blocked by the protrusion 160a, the interval between the light irradiated one frame before and one frame after is minimized, and the blur caused by the movement of the subject is minimized. Is.

Further, the chopper drive unit 17 is constructed so as to be movable in the direction with respect to the lamp 15, as shown by the arrow in FIG. That is, the distance R between the rotation center 17a of the chopper 16 shown in FIG. 9 and the luminous flux from the lamp (shown by the dotted circle) can be changed. For example, in the state shown in FIG. 9, since the distance R is considerably small, the amount of illumination light is small. By increasing the distance R (keeping the chopper drive unit 17 away from the lamp 15), the notch portion through which the light flux can pass becomes longer, so that the irradiation time becomes longer and the amount of illumination light can be increased. As mentioned above, the newly generated spectroscopic image may not be sufficient as S / N, and if one of the signals required for generation is saturated, the correct calculation was performed. Therefore, it is necessary to control the amount of illumination light. The chopper 16 and the chopper drive unit 17 are responsible for this light amount adjustment. Further, the scope 101 connected to the light source unit 41 via the connector 11
The front end portion 103 is provided with an objective lens 19 and a solid-state image sensor 21 such as a CCD (hereinafter simply referred to as CCD). The CCD in the present embodiment is a single plate type (CCD used for a simultaneous electronic endoscope), and is a primary color type. The arrangement of the color filters is shown in FIG. Also,
The spectral sensitivity characteristics of RGB are shown in FIG. Also,
The light guiding section 102 includes a light guide 14 for guiding the light emitted from the light source section 41 to the tip section 103, a signal line for transmitting an image of the subject obtained by the CCD to the main processing unit 43, and a treatment. The forceps channel 28 etc. for performing are provided. A forceps port 29 for inserting forceps into the forceps channel 28 is provided near the operation unit 104.

Further, the main body processing device 43 is connected to the scope 101 via the connector 11 like the light source unit 41. The main body processing device 43 is provided with a CCD drive 431 for driving the CCD 21. Further, it has a luminance signal processing system and a color signal processing system as a signal circuit system for obtaining a normal image. The luminance signal processing system includes a contour correction unit 432 that is connected to the CCD 21 and performs contour correction, and a luminance signal processing unit 434 that generates a luminance signal from the data corrected by the contour correction unit 432. Further, the color signal processing system is C
It is connected to the CD 21 and is connected to the outputs of the sample hold circuits (S / H circuits) 433a to 433c and S / H circuits 433a to 433c that sample the signals obtained by the CCD 21 and generate RGB signals. The color signal processing unit 435 that performs generation is included. Further, a normal image generation unit 437 that generates one normal image from the outputs of the luminance signal processing system and the color signal processing system is provided, and the normal image generation unit 437 transmits the Y signal to the display monitor 106 via the switching unit 439. The RY signal and the BY signal are sent. On the other hand, as a signal circuit system for obtaining a spectral image, the S / H circuit 43
A matrix calculation unit 436 is provided at the outputs of 3a to 433c, and a predetermined matrix calculation is performed on the RGB signals. The matrix calculation means a process of performing addition processing or the like on the color image signals and multiplying the matrix obtained as described above. In the present embodiment, a method using electronic circuit processing (processing by hardware using an electronic circuit) will be described as a method of this matrix operation. However, like the embodiments described later, numerical data processing is performed. (Processing by software using a program) may be used. In addition, it is possible to use a combination of these when implementing.

FIG. 15 shows a circuit diagram of the matrix operation unit 436. The RGB signals are resistor groups 31a to 3 respectively.
It is input to the amplifiers 32a to 32c via 1c.
Each resistor group has a plurality of resistors to which RGB signals are respectively connected, and the resistance value of each resistor is a value according to the matrix coefficient. That is, the configuration is such that the amplification factor of the RGB signal is changed by each resistance, and addition (or subtraction) may be performed by the amplifier. The output of each of the amplifiers 32a to 32c becomes the output of the matrix calculation unit. In other words, this matrix operation part
So-called weighted addition processing is performed. The resistance value of each resistor used here may be variable. The outputs of the matrix calculation unit 436 are connected to the integration units 438a to 438c, respectively, and after the integration calculation is performed, they are sent to the display monitor 106 as the respective spectral image signals ΣF _{1 to} ΣF ₃ via the switching unit 439. .
The switching unit 439 switches between a normal image and a spectral image, and can switch between spectral images. That is, the operator can selectively display the normal image, the spectral image by ΣF ₁ , the spectral image by ΣF ₂ , and the spectral image by ΣF ₃ . Further, any two or more images may be simultaneously displayed on the display monitor 106. In particular, when the normal image and the spectral image can be displayed simultaneously, it is possible to easily compare the normal image and the spectral image, which are generally observed, with each feature (the feature of the normal image is the color degree). Is easy to observe, similar to normal visual observation. The characteristic of the spectral image is that it is possible to observe certain blood vessels that cannot be observed in the normal image.) Is.

Next, the operation of the electronic endoscope apparatus 100 according to the present embodiment will be described in detail with reference to FIG. In the following, the operation when observing a normal image will be described first, and the operation when observing a spectral image will be described later. First, the operation of the light source unit 41 will be described. Based on a control signal from the control unit 42, the chopper drive unit 17 is set at a predetermined position, and the chopper 1
Rotate 6. The luminous flux from the lamp 15 is a chopper.
A light guide 14 which is an optical fiber bundle provided in the connector 11 at the connecting portion between the scope 101 and the light source unit 41 by the condenser lens after passing through the 16 cutout portions.
Is condensed at the incident end of. The condensed light flux passes through the light guide 14 and is irradiated into the body of the subject from the illumination optical system provided at the tip portion 103. The irradiated light flux is reflected inside the subject and passes through the objective lens 19 and the CCD 21.
At, signals are collected for each color filter shown in FIG. The collected signals are input in parallel to the luminance signal processing system and the color signal processing system. Brightness signal system contour correction unit 4
The signals collected for each color filter are added to each pixel and input to the pixel 32, and after the contour correction, the luminance signal processing unit 434.
Entered in. The luminance signal processing unit 434 generates a luminance signal and inputs it to the normal image generation unit 437. On the other hand, the signals collected by the CCD 21 are input to the S / H circuits 433a to 433c for each filter, and R, G, B signals are generated respectively. Further, for the R, G, B signals, a color signal processing unit 435 generates a color signal, and a normal image generation unit 437 generates a Y signal, an R-Y signal, and a B-Y signal from the luminance signal and the color signal. Then, the normal image of the subject is displayed on the display monitor 106 via the switching unit 439.

Next, the operation for observing the spectral image will be described. It should be noted that description of operations that perform the same operation as observation of a normal image is omitted here. The operator is the main body 1
05 keyboard or scope 10
By operating a switch or the like provided in the first operation unit 104, an instruction to observe a spectral image from a normal image is issued. At this time, the control unit 42 changes the control states of the light source unit 41 and the main body processing device 43. Specifically, the amount of light emitted from the light source unit 41 is changed as necessary. As described above, it is not desirable that the output from the CCD 21 be saturated, so the amount of illumination light is made smaller than in a normal image. It is also possible to control so that the output signal from the CCD does not saturate and to change the illumination light amount in the range where it does not saturate. Further, as a control change to the main body processing device 43, the signal output from the switching unit 439 is changed from the normal image generation unit 437 to the integration units 438a to 438c.
Switch to the signal output from. In addition, the S / H circuit 43
The outputs of 3a to 433c are the matrix calculation unit 436.
Then, the amplification / addition processing is performed, and the amplified / added processing is output to the integrating units 438a to 438c according to each band. Chopper-1
Even if the illumination light amount is reduced in step 6, the integrating unit 438a
To 438c, the signal strength can be increased and the S / N ratio can be increased as shown in FIG.
It is possible to obtain a spectral image with improved

The specific matrix processing according to this embodiment will be described below. In the present embodiment, from the RGB spectral sensitivity characteristics shown by the solid lines in FIG. 6, the ideal narrow band pass filters F _{1 to} F shown in FIG.
₃ (Here, the transmission wavelength range is F ₁ : 590nm-620n
_{m, F 2: 520nm-560nm} , F 3: 400nm-440nm and the) bandpass filter close to (hereinafter referred to as quasi-bandpass filter) If an attempt is made to create a, the above-mentioned (1) from equation (5) The following matrix is optimal according to the contents shown in.

[0017]

[Equation 9] Further, when the correction is performed according to the contents shown in the expressions (6) and (7), the following correction coefficient is obtained.

[0018]

[Equation 10] The spectrum of the light source shown in equation (6) is shown in FIG.
The reflection spectrum of the living body of interest shown in the equation (7) uses the foreseeing information with that shown in FIG. Therefore, the processing performed in the matrix section is mathematically equivalent to the following matrix calculation.

[0019]

[Equation 11] By performing this matrix operation, pseudo filter characteristics (shown as the characteristics of the filter pseudo F _{1 to} F _{3 in} FIG. 6) are obtained. That is, the matrix processing described above uses the pseudo bandpass filter (matrix) previously generated as described above for the color image signal,
A spectral image signal is created. An example of an endoscopic image generated by using this pseudo filter characteristic is shown below. The subject is the surface of the mucous membrane of the digestive tract, and FIG. 10 is a normal endoscopic image. 11 is a spectral image corresponding to the bandpass filter F3 shown in FIG. 6 obtained after the processing, and FIG. 12 is a spectral image corresponding to the bandpass filter F2 shown in FIG. 6 obtained after the processing, and FIG.
Is the bandpass filter F shown in FIG. 6 obtained after processing.
It is a spectral image corresponding to 1. Each of the spectral images shown in FIGS. 11 to 13 clearly extracts blood vessel patterns equivalent to or more than the normal image shown in FIG. In particular, the band abbreviations shown in FIG. 11 and FIG.
Spectral images using filters of 400-approximately 440 nm and approximately 520-approximately 560 nm extract blood vessel patterns more clearly. As is clear from the above, according to the present embodiment, a pseudo narrowband filter is generated using a color image signal for generating a normal electronic endoscopic image (normal image). This makes it possible to obtain a spectral image in which a blood vessel pattern is clearly displayed, without using an optical wavelength narrow bandpass filter for spectral images.

Further, in particular, in the wavelength regions of approximately 400 to approximately 440 nm and approximately 520 to approximately 560 nm, it is possible to obtain a spectral image in which the blood vessel pattern is more clearly extracted. The second embodiment according to the present invention will be described below with reference to FIG. FIG. 14 is a block diagram of electronic endoscope apparatus 100 according to the present embodiment. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. This embodiment is mainly the same as the first embodiment,
The light source unit that controls the amount of illumination light is different. In this embodiment, the amount of light emitted from the light source unit is controlled not by the chopper but by controlling the lamp current. Specifically, the lamp 15 shown in FIG.
6'is provided. The operation of this embodiment is as follows.
The control unit 42 controls the current flowing through the lamp 15 so that any of the RGB color image signals is not saturated. As a result, the current used for the lamp 15 to emit light is controlled, so that the amount of light changes according to the magnitude of the current. Note that other operations are the same as those in the first embodiment, and therefore omitted here. According to the present embodiment, as in the first embodiment, it is possible to obtain a spectral image in which the blood vessel pattern is clearly displayed. Further, in the present embodiment, compared to the light quantity control method using the chopper as in the first embodiment,
There is an advantage that the control method is simple.

The third embodiment according to the present invention will be described below with reference to FIG. This embodiment mainly differs from the first embodiment in the matrix operation unit 436. In the first embodiment, the matrix operation is performed by so-called hardware processing by an electronic circuit, but in the present embodiment, this operation is performed by numerical data processing (processing by software using a program). FIG. 16 shows a specific configuration of the matrix calculation unit in this embodiment. The matrix calculation unit has an image memory 50 that stores color image signals of RGB. Further, it has a counting register 51 in which the respective values of the matrix A ′ shown in the equation (11) are stored as numerical data. The counting register 51 and the image memory 50 include multipliers 53a to 53i.
And the multipliers 53a, 53d, 53g are connected to
It is connected to the multiplier 54a, and the output of the multiplier 54a is
Is connected to the integrating unit 438a. Also, the multiplier 5
3b, 53e, and 53h are connected to the multiplier 54b, and the output thereof is connected to the integrating unit 438b. Also, the multiplier 5
3c, 53f, and 53i are connected to the multiplier 54c, and the output is connected to the integrating unit 438c. As the operation of this embodiment, the input RGB image data is once stored in the image memory 50. Next, each count of the matrix A'from the count register 51 is multiplied by the RGB image data stored in the image memory 50 by the multiplier by a calculation program stored in a predetermined storage device (not shown).

Note that FIG. 16 shows an example in which the R signal and each matrix count are multiplied by the multipliers 53a to 53c. Further, as shown in the figure, the G signal and each matrix count are multiplied by the multipliers 53d to 53f, and the B signal and each matrix count are multiplied by the multipliers 53g to 53i. The outputs of the multipliers 53a, 53d, and 53g of the data multiplied by the matrix count are output to the multiplier 5
4a, the outputs of the multipliers 53b, 53e, 53h are multiplied by the multiplier 54b, and the outputs of the multipliers 53c, 53f, 53i are multiplied by the multiplier 54c. Multiplier 54
The output of a is sent to the integrating unit 438a. Further, the outputs of the multiplier 54b and the multiplier 54c are respectively added by the accumulator 438.
b, 438c. According to this embodiment, the first
Similar to the above embodiment, a spectral image in which the blood vessel pattern is clearly displayed can be obtained. Further, in the present embodiment, since the matrix processing is not performed by hardware as in the first embodiment but is performed by software, it is possible to promptly deal with, for example, changing each matrix count. it can. In addition, the matrix count is stored not only as the result value, that is, as the matrix A ′, but separately for S (λ), H (λ), R (λ), G (λ), and B (λ). When the matrix A ′ is calculated and used according to, it is possible to change only one element in the matrix A ′, which improves convenience.
For example, it is possible to change only the spectral characteristic S (λ) of the illumination light.

Next, a fourth embodiment according to the present invention will be described with reference to FIG. This embodiment is mainly based on the first embodiment and the light source unit 41 and the CCD 21.
Are different. In the first embodiment, the CCD 2
1 is provided with the color filter shown in FIG. 2, and a color signal is generated by this color filter, which is a so-called simultaneous system, whereas in the present embodiment, the illumination light is RG.
A so-called frame-sequential method for illuminating in the order of B to generate color signals is used. In the light source unit 41 in the present embodiment, a diaphragm 25 is provided in front of the lamp 15, and an RGB filter 23 is provided further in front of the diaphragm 25. Further, the diaphragm 25 is connected to the diaphragm control unit 24, and limits the luminous flux transmitted through the luminous flux emitted from the lamp 15 in accordance with a control signal from the diaphragm control unit 24 to change the light amount. In addition, the RGB rotation filter 23
It is connected to the rotation filter control unit 26 and rotates at a predetermined rotation speed. As the operation of the light source unit in the present embodiment, the luminous flux output from the lamp 15 is limited to a predetermined amount by the diaphragm 25, and the luminous flux transmitted through the diaphragm 25 is RGB.
By passing through the filter, R ・ G at every predetermined time
-The light of each B is output from the light source unit.
Further, each illumination light is reflected inside the subject, and the CCD
The light is received at 21. The signal obtained by the CCD 21 is distributed by a switching unit (not shown) provided in the endoscope apparatus main body 105 according to the irradiation time, and the S / H circuit 4
33a to 433c, respectively. That is, when the illumination light is emitted from the light source unit 41 through the R filter, the signal obtained by the CCD 21 is the S / H circuit 4
It will be input to 33a. Note that other operations are the same as those in the first embodiment, and therefore omitted here.

According to the present embodiment, as in the first embodiment, it is possible to obtain a spectral image in which the blood vessel pattern is clearly displayed. Further, in the present embodiment, unlike the first embodiment, it is possible to enjoy the merits of the so-called frame sequential method. It should be noted that this merit includes, for example, those of the following fifth embodiment. Further, in the above-described embodiment, the illumination light amount (light amount from the light source unit) is controlled and adjusted in order to avoid saturation of the RGB color signals. On the other hand, there is also a method of adjusting the electronic shutter of the CCD. In the CCD, an electric charge proportional to the intensity of the incident light is accumulated within a fixed time, and the amount of the electric charge is used as a signal. An electronic shutter corresponds to this accumulation time. By adjusting the electronic shutter, the charge accumulation amount, that is, the signal amount can be adjusted. Therefore, as shown in FIG. 18, by obtaining the RGB color image in the state where the charge accumulation time is sequentially changed, Similar spectral images can be obtained. That is, in each of the above-described embodiments, the control of the amount of illumination light is used to obtain a normal image, and when obtaining a spectral image, it is possible to avoid saturation of the RGB color signals by changing the electronic shutter. Is. Next, a fifth embodiment according to the present invention will be described with reference to FIG.
Like the fourth embodiment, the present embodiment mainly uses the frame-sequential method and takes advantage of this advantage. By weighting the charge accumulation time by the electronic shutter control in the fourth embodiment, the generation of spectral image data can be simplified. That is, in this embodiment, the CCD drive 431 that can change the charge storage time of the CCD is included. The rest of the configuration is the same as that of the fourth embodiment, and is omitted here.

As the operation of the present embodiment, as shown in FIG. 19, when the respective illumination light is irradiated through the RGB rotary filter, the charge storage time by the electronic shutter in the CCD is changed. Here, the illumination light is R
The charge storage time of the CCD in each case of G and B is td _r , td _g , td _b (in the figure, td _b is omitted because the B color image signal does not have a storage time).
And For example, the F3 pseudo filter image in the case of performing the matrix processing shown in the equation (11) is obtained from an RGB image normally obtained by an endoscope,

[Equation 12] Is calculated, the charge accumulation time by the electronic shutter control for each RGB in FIG.

[Equation 13] It should be set so that Further, in the matrix portion, a signal obtained by simply inverting only the R and G components and the B component are added. This makes it possible to obtain the same spectral image as that of the first to fourth embodiments. According to this embodiment,
Similar to the fourth embodiment, it is possible to obtain a spectral image in which the blood vessel pattern is clearly displayed. Further, in the present embodiment, as in the fourth embodiment, a frame sequential method is used for creating color signals, and the charge accumulation time can be made different for each color signal by using an electronic shutter. Therefore, in this way, in the matrix part,
It suffices to simply perform addition and difference processing, and the processing can be simplified. Next, a sixth embodiment according to the present invention will be described. This embodiment is mainly the first
The color filter provided in the CCD is different from that of the embodiment. In the first embodiment, an RGB primary color type color filter is used as shown in FIG. 2, whereas in the present embodiment, a complementary color type color filter is used. As shown in FIG. 20, the complementary color filter array is composed of G, Mg, Ye, and Cy elements. The relationship between each element of the primary color type color filter and each element of the complementary color type color filter is Mg = R + B, Cy = G + B,
Ye = R + G.

In this case, all pixels of the solid-state image pickup device are read out, and the image from each color filter is subjected to signal processing or image processing. Further, if the equations (1) to (11) for the primary color filter are modified in the case of the complementary color filter, the following equation (15) yields (2)
It becomes like the formula 1). However, the characteristics of the target narrowband bandpass filter are the same.

[0027]

[Equation 15]

[Equation 16]

[Equation 17]

[Equation 18]

[Formula 19]

[Equation 20]

[Equation 21] Further, FIG. 21 shows the spectral sensitivity characteristics in the case of using a complementary color filter, the target bandpass filter, and the characteristics of the pseudo bandpass filter obtained by the above equations (15) to (21). When the complementary color filter is used, the S / H circuit shown in FIG.
-It goes without saying that it is not G / B, but G / Mg / Cy / Ye. According to the present embodiment, as in the first embodiment, it is possible to obtain a spectral image in which the blood vessel pattern is clearly displayed. In addition, in the present embodiment, it is possible to enjoy the advantages of using the complementary color type color filter. Although the respective embodiments of the present invention have been described above, the present invention may be used by combining the above-described embodiments in various ways, and modifications may be made without departing from the spirit of the present invention. For example, with respect to all of the above-described embodiments, the operator can create a new pseudo bandpass filter by himself / herself at other timings during the clinical stage and apply it to the clinical stage. That is, FIG. 4 shows the first embodiment.
The control unit 42 in the inside is provided with a design unit (not shown) capable of calculating and calculating matrix coefficients. Thereby, by inputting the conditions through the keyboard provided in the endoscope body shown in FIG. 3, a pseudo bandpass filter suitable for obtaining the spectral image that the operator wants to know is newly designed, and The calculated matrix coefficient (corresponding to each element of the matrix A of the equations (9) and (19)) is corrected by the correction coefficient (corresponding to each element of the matrix K of the equations (10) and (20)). Matrix coefficient ((1
By setting (corresponding to each element of the matrix A ′ of the equations (1) and (21)) in the matrix calculation unit 436 in FIG. 4, it can be applied to immediate clinical practice. FIG. 22 shows a flow up to application. Explaining this flow in detail, first, the operator inputs target band-pass filter information (for example, wavelength band or the like) via a keyboard or the like. As a result, the matrix A ′ is calculated together with the characteristics of the light source / color filter already stored in the predetermined storage device or the like, and as shown in FIG. 21, the matrix of the matrix A ′ is calculated together with the characteristics of the target bandpass filter. The calculation result (pseudo bandpass filter) by A'is
It is displayed on the monitor as a spectrum diagram. After confirming the calculation result, the operator sets the newly created matrix A ′, if any, and sets the matrix A ′ to generate an actual endoscopic image.
Also, with this, the newly created matrix A '
Is stored in a predetermined storage device and can be used again in accordance with a predetermined operation by the operator. As a result, the operator can generate a new bandpass filter based on his or her own experience without being restricted by the existing matrix A ′, which is highly effective especially when used for research.

In addition to this, the following modified examples can be considered. For example, in the above embodiment, (12)
In the generation of the F3 pseudo filter image shown in the formula, the R component is so small that it can be ignored with respect to the G and B components. In this case,

[Equation 14] It is not necessary to use the R image signal or the numerical data to approximate At this time, even if the signal of the R image or the numerical data is saturated, it does not affect the processing in the matrix part. Therefore, if the signal of the G image and the B image or the numerical data is not saturated, the illumination light amount or Electronic shutter control may be performed.

[0029]

As described in detail above, according to the present invention, since a spectral image signal is created using a color image signal obtained from a normal electronic endoscope image, a light source section dedicated to a spectral image is used. It is possible to obtain a spectral image in which a blood vessel pattern or the like is clearly displayed without providing an optical wavelength narrow band bandpass filter.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a signal flow when a spectral image signal is created from a color image signal according to a first embodiment of the present invention.

FIG. 2 is a conceptual diagram showing an integral calculation of a color image signal according to the first embodiment of the invention.

FIG. 3 is an external view of the electronic endoscope apparatus according to the first embodiment of the present invention.

FIG. 4 is a block diagram of the electronic endoscope apparatus according to the first embodiment of the present invention.

FIG. 5 is a diagram showing an arrangement of color filters according to the first embodiment of the present invention.

FIG. 6 is a diagram showing a spectral sensitivity characteristic of each color filter according to the first embodiment of the present invention.

FIG. 7 is a spectrum diagram of a light source according to the first embodiment of the present invention.

FIG. 8 is a reflection spectrum diagram of a living body according to the first embodiment of the present invention.

FIG. 9 is an external view of a chopper according to the first embodiment of the present invention.

FIG. 10 is a normal endoscopic image according to the first embodiment of the present invention.

FIG. 11 is a spectral image corresponding to the bandpass filter F3 according to the first embodiment of the present invention.

FIG. 12 is a spectral image corresponding to the bandpass filter F2 according to the first embodiment of the present invention.

FIG. 13 is a spectral image corresponding to the bandpass filter F1 according to the first embodiment of the present invention.

FIG. 14 is a block diagram of an electronic endoscope apparatus according to a second embodiment of the present invention.

FIG. 15 is a circuit diagram of a matrix operation unit according to the second embodiment of the present invention.

FIG. 16 is a configuration diagram of a matrix calculation unit according to a third embodiment of the present invention.

FIG. 17 is a block diagram of an electronic endoscope apparatus according to a fourth embodiment of the present invention.

FIG. 18 is a diagram showing a charge accumulation time in the fourth embodiment according to the present invention.

FIG. 19 is a diagram showing a charge storage time in the fifth embodiment according to the present invention.

FIG. 20 is a diagram showing an arrangement of color filters according to a sixth embodiment of the present invention.

FIG. 21 is a diagram showing the spectral sensitivity characteristic of each color filter in the sixth embodiment of the present invention.

FIG. 22 is a flow chart diagram at the time of matrix calculation in a modified example according to the present invention.

[Explanation of symbols]

11 connector 14 Light guide 15 lamps 16 chopper 17 Chopper drive 19 Objective lens 21 Solid-state image sensor 23 RGB filter 24 Aperture controller 25 aperture 26 RGB Rotation Filter Control Unit 28 forceps channel 29 Forceps mouth 31 Amplifier 32 resistance group 33 adder 41 Light source 42 Control unit 43 Main processing unit 50 image memory 51 Count register 53 Multiplier 54 multiplier 101 Scope 102 Central 103 tip 104 Operation part 105 Endoscope device body 106 display monitor

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H04N 9/04 H04N 9/04 Z F term (reference) 2H040 BA00 BA09 CA10 GA02 GA11 4C061 CC06 MM03 RR04 RR15 RR17 SS21 WW10 5C054 AA01 CA04 CC07 CD03 CG02 EA01 EA05 EE06 EE08 EF01 FC11 GD03 HA12 5C065 AA04 BB14 BB41 CC01 DD02 EE05 EE06

Claims (18)

[Claims] 1. An object is irradiated with light from a light source for illumination,
An electronic endoscope apparatus for obtaining a color image signal by a solid-state image sensor, comprising: an arithmetic unit for generating a spectral image signal from the color image signal. 2. The electronic endoscope apparatus according to claim 1, wherein the arithmetic unit generates the spectral image signal from the color image signal by electronic circuit processing. 3. The electronic endoscope apparatus according to claim 1, wherein the arithmetic unit generates the spectral image signal from the color image signal by numerical data processing. 4. The electronic endoscope apparatus according to claim 1, further comprising a light amount limiting unit that controls the amount of light emitted from the illumination light source. 5. The light amount control unit reduces the light amount when acquiring the spectral image signal as compared to when acquiring the color image signal.
The described electronic endoscope apparatus. 6. The electronic endoscope apparatus according to claim 4, wherein the light amount control unit has a chopper that blocks the light at a predetermined time interval. 7. The electronic endoscope apparatus according to claim 4, wherein the light amount control unit includes a current control unit that controls a current flowing through a lamp of the illumination light source. 8. The electronic endoscope apparatus according to claim 1, further comprising an electronic shutter control unit that controls an electronic shutter that determines a charge accumulation time by the solid-state imaging device. 9. The electronic endoscope apparatus according to claim 8, wherein the electronic shutter control section can independently control the charge storage time for each color image signal. 10. A light amount limiting unit that controls the amount of light emitted from the illumination light source, and an electronic shutter control unit that controls an electronic shutter that determines a charge accumulation time by the solid-state imaging device, The light amount and the charge storage time are controlled simultaneously.
The described electronic endoscope apparatus. 11. The apparatus according to claim 1, further comprising a setting unit capable of changing a predetermined coefficient used when generating the predetermined spectral image signal from the color image signal.
The described electronic endoscope apparatus. 12. The electronic device according to claim 1, wherein a color image generated based on the color image signal and a spectral image generated based on the spectral image signal can be switched and displayed. Endoscope device. 13. The color image generated based on the color image signal and the spectral image generated based on the spectral image signal can be displayed on the same screen. Electronic endoscope device. 14. The electronic device according to claim 1, wherein the arithmetic unit generates the spectral image signal from the color image signal using a predetermined coefficient obtained based on a color sensitivity characteristic. Endoscope device. 15. The color image signal is further calculated by using the predetermined coefficient obtained based on at least one of the spectral characteristic of the illumination light source and the reflection characteristic of the subject. 15. The electronic endoscope apparatus according to claim 14, wherein the spectral image signal is generated from the. 16. The electronic endoscope apparatus according to claim 1, wherein the spectral image signal includes a negative signal. 17. The electronic endoscope apparatus according to claim 1, wherein the color image signal is an RGB signal or a GCyMgYe signal. 18. The spectral image signal is approximately 400 nm to approximately 4 nm.
Image signal in the wavelength range of 40 nm, or approximately 520 nm to approximately 560 nm
2. The image signal in the wavelength region of
An electronic endoscope apparatus according to claim 17.